<h2>DESCRIPTION</h2>

<em><b>r.describe</b></em> prints a terse listing of category values found in
a user-specified raster map layer.

<p>
<em><b>r.describe</b></em> ignores the current geographic region and mask, and
reads the full extent of the input raster map.  This functionality is useful if the
user intends to <em>reclassify</em> or <em>rescale</em> the data, 
since these functions (<em><a href="r.reclass.html">r.reclass</a></em> and
<em><a href="r.rescale.html">r.rescale</a></em>) 
also ignore the current <em>geographic region</em>
and <em>mask</em>.

<p>The <em><b>nv</b></em> parameter sets the string to be used to represent <tt>NULL</tt> 
values in the module output; the default is '*'.

<p>The <em><b>nsteps</b></em> parameter sets the number of quantisation steps to divide into 
the input raster map.

<h2>NOTES</h2>

<h3>FLAGS</h3>

If the user selects the <b>-r</b> flag, a range of category values found in 
the raster map layer will be printed. The range is divided into three groups: 
negative, positive, and zero. If negative values occur, the minimum and maximum 
negative values will be printed. If positive values occur, the minimum and maximum 
positive values will be printed. If zero occurs, this will be indicated. The range 
report will generally run faster than the full list (the default output).

<p>
The <b>-d</b> flag can be used to force <em>r.describe</em> to respect the current region
extents when repoting raster map categories. The default behavior is to read the full 
extent of the input raster map.

<p>If the <b>-1</b> flag is specified, the output appears with one category value/range per line.

<p>The <b>-n</b> flag suppresses the reporting of <tt>NULL</tt> values.

<h2>EXAMPLES</h2>

The following examples are from the Spearfish60 sample Location:

<p>
# Print the full list of raster map categories:
<div class="code"><pre>
r.describe landcover.30m 
* 11 21-23 31 32 41-43 51 71 81-83 85 91 92
</pre></div>
<p>
# Print the raster range only:
<div class="code"><pre>
r.describe -r landcover.30m
11 thru 92
*
</pre></div>

# Print raster map category range, suppressing nulls:
<div class="code"><pre>
r.describe -n landcover.30m 
11 21-23 31 32 41-43 51 71 81-83 85 91 92
</pre></div>
<p>
# Print raster map categories, one category per line:
<div class="code"><pre>
r.describe -1 geology 

*
1
2
3
4
5
6
7
8
9
</pre></div>
<p>
<h2>SEE ALSO</h2>

<em>
<a href="g.region.html">g.region</a>,
<a href="r.mask.html">r.mask</a>,
<a href="r.reclass.html">r.reclass</a>,
<a href="r.report.html">r.report</a>,
<a href="r.rescale.html">r.rescale</a>,
<a href="r.stats.html">r.stats</a>,
<a href="r.univar.html">r.univar</a>

</em>

<h2>AUTHOR</h2>

Michael Shapiro, U.S. Army Construction Engineering Research Laboratory

<!--
<p>
<i>Last changed: $Date$</i>
-->
